Like Pat said it will take a while to dry,, but once dry you can finish over it,, I have been using a walnut oil alkyd medium that makes the oil paint dry faster,,,if you used the oil alkyd medium to mix your ochre in ,, it would dry quicker,,, and also it depends on the climate you are in how fast or slow it will dry,,,,
acrylic paint will not smear,,,if you put a finish on it,,, you might want to experiment on a scrap piece of wood,,, to see what works the best for you,,, and how long you need to let it dry